Sigma Serpentis
Sigma Serpentis, Latinized from σ Serpentis, is a star in the equatorial constellation Serpens. It is faintly visible to the naked eye with an apparent visual magnitude of +4.82.[2] Based upon an annual parallax shift of 36.67 mas as seen from Earth, it is located 89 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −49 km/s.[5]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Serpens |
| Right ascension | 16h 22m 04.34753s[1] |
| Declination | +01° 01′ 44.5534″[1] |
| Apparent magnitude (V) | +4.82[2] |
| Characteristics | |
| Spectral type | F3 V[3] or A9 Ib/II[4] |
| U−B color index | +0.025[2] |
| B−V color index | +0.338[2] |
| Astrometry | |
| Radial velocity (Rv) | −49.3±0.9[5] km/s |
| Proper motion (μ) | RA: −158.40[1] mas/yr Dec.: +49.56[1] mas/yr |
| Parallax (π) | 36.67 ± 0.33 mas[1] |
| Distance | 88.9 ± 0.8 ly (27.3 ± 0.2 pc) |
| Absolute magnitude (MV) | +2.63[6] |
| Details | |
| Mass | 1.58±0.01[7] M☉ |
| Luminosity | 7.7[7] L☉ |
| Surface gravity (log g) | 4.05[6] cgs |
| Temperature | 6,952[8] K |
| Metallicity [Fe/H] | −0.01[8] dex |
| Rotational velocity (v sin i) | 77.7[6] km/s |
| Age | 1.15±0.10[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Barry (1970) assigned this star a stellar classification of F3 V,[3] indicating an ordinary F-type main-sequence star. However, Houk and Swift (1999) classified it as A9 Ib/II,[4] suggesting instead that this is an evolved F-type bright giant/supergiant. It is about one billion[8] years old and is spinning with a projected rotational velocity of 77.7 km/s.[6] The star has an estimated 1.58[7] times the mass of the Sun and is radiating 7.7[7] times the Sun's luminosity from its photosphere at an effective temperature of 6,952 K.[8]
References Edit
- ^ a b c d e van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d Cousins, A. W. J. (1984), "Standardisation of broad band photometry of equatorial standards", South Africa Astronomical Observatory Circular, 8: 59–67, Bibcode:1984SAAOC...8...59C.
- ^ a b Barry, Don C. (January 1970), "Spectral Classification of a and F Stars", Astrophysical Journal Supplement, 19: 281, Bibcode:1970ApJS...19..281B, doi:10.1086/190209.
- ^ a b Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey, Ann Arbor: Dep. Astron., Univ. Michigan, 5, Bibcode:1999MSS...C05....0H.
- ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c d Paunzen, E.; et al. (July 2014), "Investigating the possible connection between λ Bootis stars and intermediate Population II type stars", Astronomy & Astrophysics, 567: 8, arXiv:1406.3936, Bibcode:2014A&A...567A..67P, doi:10.1051/0004-6361/201423817, S2CID 56332289, A67.
- ^ a b c d Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
- ^ a b c d e Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics, 551: 4, arXiv:1301.5651, Bibcode:2013A&A...551L...8P, doi:10.1051/0004-6361/201220364, S2CID 56420519, L8.
- ^ "sig Ser". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-10-20.
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